The mechanics of lying -- why some people take lying to extremes, and what might be happening in their minds when they do.

Recent headlines involving Lance Armstrong's doping confession to Oprah and the Manti Te'o Internet girlfriend hoax have us wondering what it is that leads some people to lie. So we turned to experts to help explain what might be happening inside the heads of those who tell lies.

"Different brains will deliver different behaviors when it comes to lying," said Dr. Mona Lisa Schulz, who studied behavioral neuroscience at Boston School of Medicine. For example, Armstrong lied for years about taking performance-enhancing drugs, while the Te'o hoax came to a relatively quick end once it was uncovered. "Some people can put a blinder up so they can ignore other people's emotions to focus on the task at hand ... so this is for a short period of time, for survival. It can also be done for a long period of time."

Activity related to behavior and thus to lying is centered in the frontal lobe, Schulz said, which is the part of the brain where empathy, emotions, relationships and intuition are all connected.

"People who are naturally empathic or emotional have a hard time ignoring the emotions of others, which makes lying for longer periods of time very difficult," she said. "For some people, their brain's wiring never goes to that intersection in the frontal lobe. Those lines are not functioning. Either it was genetic and they were born without them or they were raised in an environment that didn't foster all those qualities. It is easier for these people to lie for longer periods of time."

Taking another view, health psychology expert Matthew James, Ph.D. and chairman of the Association for Integrative Psychology, said

people who tell a lie repeatedly can actually start to believe it.

"It becomes pathological," he said. "It becomes part of who they are."

So why do some liars eventually come clean, like Armstrong did to Oprah?

"Some people become anxious to let the truth out because they aren't bad people, they just got caught up in their story," James said. "When you look at the physiology of the liar when the lie is revealed, you can almost see a relief — like a weight has been lifted off of them."

Schulz said a sudden life change can also trigger the need to tell the truth.

"Something that can override the wiring of your brain and put an end to destructive behavior is a crisis or a life threatening illness," she said. "It does something to your limbic system, or your empathy circuits. ... and a person is then faced with a choice where they can choose to change."